Category: AngularJS

Its been a while since I visited my pyschiatrist and now, Chiropractor Dr. Pear – Perspective Readjustment Specialist. Last time, he helped me cope up an aggressive experience with pair programming. The front-desk handed me a big chunk of forms to fill up my software history.

Years of experiencing web frameworks: About 18.
First framework of pain: JSP Model 2, perhaps Applet, can’t remember.
Latest framework of pain: AngularJS
History of major pain points: EJB, WebSphere, WebLogic, Spring, Fusion Middleware, Wicket, ASP.Net Web/MVC, SharePoint, Grails, SpringBoot, Backbone, Ember, AngularJS and innumerable minor ones.
What type of pain is this? (Select one: Sharp, Shooting, Numb): All of them
Approximate location of pain: Initially Back-end. Then moved to Front-end.
Exact location of pain: Depends on Mood.
Frequency of occurrence of major pain: About every 18 months.

I physically submitted the forms and started checking my tweet feed. New tweets from dzone on Top 20 Javascript frameworks; AngularJS Jobs; Best 35 CSS Frameworks; Top 15 build tools for Javascript; AngularJS vs.., no wonder I needed a therapy.

The nurse called me in and after the initial handshake of pulses and vital stats, she said 200. I was idly looking at the magazines – PlayWeb, Maximum Frameworks… Dr. Pear entered after a knock.

Dr. Pear (browsing thru my history rather than looking at me): Oh, Hello! Its been a while from your last visit.Me: Yes, Doctor.Dr. Pear: And what brings you here?Me: Well, Ive been spinning my head with the next web application framework and I haven’t been able to decide quite…Dr. Pear: Well, the short answer is “As a consultant you should learn all of them !”, ha ha ha… (after a pause) Yeah, yeah I know. Its the viral season of frameworks. The Javascriptarix flu shot we gave last month was really a placebo. So what kind of framework you are really looking for?Me: (a bit hesitantly) Not sure, Ive been taking the Javascript MVC Kool-aid for the last couple of years, but it looks like the pain isn’t gone…Dr. Pear looked at me a bit condescendingly and said “MVC eh? in Javascript? Didn’t you get high enough on it in the Java/.Net world?”.Me: Well, the Java web frameworks are kinda relegated to providing data services these days…

I had not finished. It must have triggered a raw nerve in him and he went on to a mini lecture of sorts.

“You see, web frameworks come in two general flavors – MVC and Component. Java failingly flirted with the Applet component model initially, and then took a stab at MVC via JSP Model 2, while ASP.Net took the component route after its success with Visual Basic. Interestingly, Java increasingly adapted the component framework model, but Microsoft abandoned ASP.Net Web in favor of ASP.Net MVC. Java/JVM probably tasted all kinds of frameworks in many levels – MVC (Struts, Stripes, Spring, Grails, Play) and Component oriented (Seam, Tapestry, JSF & Co, Wicket, GWT). The fundamental problem with MVC is – it sprays your logic and model everywhere. Many developers struggle to organize it between “what-they-are” vs “what-they-do”. As the complexity increases, the code gets re-organized by features, each of which in turn have the m-v-and-c. Add on top of that, the domain models and view-models are usually different, the whole thing about models start looking like a beauty pageant.”

He paused a second, probably aiming for me to get the pun.

“Component frameworks couple model and view tightly, because a view makes no sense without a model. But the biggest problem for them came from somewhere else: Javascript. Many pure java web frameworks are relatively stable, because of a stable and backward-compatible Servlet API. But component frameworks relied too much on encapsulating Javascript and HTML and in JS world, Friday’s release is outdated by next day Matinee show. Ajax, jQuery and related libraries innovated way too fast and library encapsulation really made no sense. When the JS libraries went unsupported, it dragged the Java frameworks along. With NodeJs, NPM-modules and unit-testing frameworks offering a vastly superior build ecosystem, life became miserable for frontend developers, bogged down by verbosity and slowness of JVM build tools.”

Me: Well, that’s exactly why I am here for. What is the JS framework you would really recommend?Dr. Pear: Of course Backbone. I love backbones, especially if they aren’t straight. Get it? Ha ha !

He realized I didn’t look at him very admiringly. He continued.

Dr. Pear: Ok. Well, I hate to say it depends, because you didn’t pay me to hear that. So let me tell you something else. With JS frameworks like Backbone, Knockout and Ember becoming first class citizens, server-side slowly mellowed down to doing CRUDGE-work (Create, Read, Update, Delete, Gather and throw Exceptions), now gloriously termed as Microservices Architecture. With AngularJS offering a complete MVC stack, it doesn’t make sense to write Views in server-side anymore.”

Me: So should I still stick with AngularJS MVW ? Besides its barrage of new vocabulary redefinitions like service, factory, provider, scope, directive, the next version 2.0 promises to be completely different and backward incompatible…Dr. Pear: Yeah, I heard that. It appears that you really need to work on your persuasion skills on convincing your team about writing in new framework every year.Me: (I looked at him awkwardly, wondering what to say)Dr. Pear: (Ignoring my awkward pause) Well, the web has to evolve. Why do you think Javascript is going bonkers with frameworks – they have to compete with rapidly advancing browser features, handheld and wearable devices. Who knows, Javascript could be running inside your brain tomorrow. Ok, so you are now tired of MVC in Javascript world also. What about Facebook ReactJS?Me: ReactJS. Yes I’ve heard of it. Isn’t that a component oriented JS framework?Dr. Pear: It sure is. You write HTML directly within Javascript or CoffeeScript or Typescript in an XML like syntax and compile them to Javascript.Me: Im not sure I like the sound of that. Thats not even the best practice.Dr. Pear: Well, its time to Refactor the Best Practices too. IMO, ReactJS may indeed work out well, because unlike the Java component frameworks, its closer to Javascript, it uses Virtual DOM providing fantastic rendering speeds and helps write isomorphic apps. If you get used to JSX, you will love it.Me: What about Services?Dr. Pear: Use one of the many flavors of Flux, Reflux, Fluxxor, Alt – the Action oriented one-way-data-flow-store.Me: Hmm, that eerily reminds me of Struts. So, there is no really a best framework?Dr. Pear: There is one – come up with your own. You will surely get a few fans.Me: What if I get bored and jump ship to another framework? What about the developers who depend on my framework?

“Send them to me!” Dr. Pear said calmly, washing his hands for no reason. “If anyone thinks JS frameworks have more than 18 months of fame, they need a Perspective Readjustment”.

As I was leaving, he gave a parting shot, “Just remember one thing, if it makes you feel any better: no matter which framework, you are solving only a singleproblem: Delivering html to a browser. And by the way, if you haven’t selected your styling framework, I am open on Saturday afternoon”.

“Er.. Thanks, I will think about it”, I said as I flipped my phone to follow @ReactJS feed on my twitter.

As I was walking out I could see him frantically typing on the screen “Successfully readjusted for component framework. Will likely come here in the next 12 months looking for Web Component and Polymer adjustment.”

Starting to learn a web framework, doesn’t matter which platform – Spring, AngularJS, Grails, Rails etc. is easy. But once you go past the elementary-school level status, a question always looms – how to accomplish tasks the framework-way versus the non-framework way?

A seemingly simple stuff like configuring environment properties at runtime (startup), took me through internals of AngularJS. For server-side folks, the technique is pretty standard: use any of .properties, .xml, .yaml and then apply a built-in framework feature. For eg. in Spring, you can using the @ConfigureProperties, for Grails, use the Config.groovy and the framework will automatically place it in grailsApplication, similar to what Rails does. But how do you do it for a purely client side application (ie ‘static’ site, that relies only on rest calls from some other server)?

AngularJS allows a Module.constant() method, where you can just specify a Javascript object and DI-it where-ever you want. Neat. But often the config values are environment specific. One of the very nice solutions is to use grunt-replace and simply provide the environment specific json at build time and grunt replaces the config values for that build. One may argue that this is the correct way to do, because it provides consistency and tracebality in CI.

But in some cases the values may not be known ahead before build and is known only at application startup. So the question is what is the AngularJS way of loading the configuration file at startup? Would have been nice to have AngularJs look for a config.json properties file at root and automatically load and inject it into a variable like $env.

Obviously, AngularJS offers so much stuff – constant, value, service, factory, provider. I thought I need to stick the $http somewhere and load the config.json file and set it to AngularJS constant or value. Then inject the constant to any controller or service.

1. Inject $http into Module.constant()

Will not work, constant accepts only an object and not services. At this point of time, it is useful to get familiar with config and run phases of AngularJS. This stackoverflow question explains succinctly.

2. Inject $http into Module.config()

Will not work. You cannot inject a AngularJS service into config. You can inject only a provider into config.

While this almost works, there is a problem: $http is an asynchronous call, so its not guaranteed that the data will be returned with the values read from the config.json. Very likely the local envConfig will be returned always.

To get around you have to make $http a sync call, which is not possible. So we go deeper into the underlying framework of AngularJS – jQuery.

Notice, that the q.responseText is a string and is converted to Json object using angular.fromJson(). Also by using angular.extend, you can merge the local envConfig with the target one – this allows you to keep some default values that you dont want to immediately expose.

5. How about profiles?

If you have multiple profiles in the config.json, you can simply use the following technique:

Remember the core principle of MVC? Clean separation of model, control and view? Many MVC frameworks, but there hardly is a single framework that provides a puritanical separation between layers. In some, the view is polluted with server-side syntax (jsp, gsp, asp), its equivalents (taglib) or specialized templates (velocity, freemarker); in some others, the server-side code is interspersed with view layer abstractions (css class, href links) or its equivalent html wrappers. One way to measure good separation is how close the view layer is to html semantics itself.

In this part, let us see how we can combine the power of Angular and simplicity of Grails (mainly because of conventions) to make a better separation of model and view.

Note: For the brevity of this post, the tests are not explained, but is included in the github. Specifically, take a look at how angular-mocks provides a cool $httpBackend object that acts as a http service for unit tests and how to invoke them in the controllerSpecs.js.

There are many ways to create restful services in Grails 2.3.x, this is one of the easiest ways – create a domain object and add a @Resource annotation. Works for prototypes, demos and really simple applications. For an advanced method, you may want to use RestController and other methods.

1. As a convention, I keep Angular controller suffix as “*Ctrl”, while Grails controllers as “*Controller”.
2. Observe that one more parameter is being added to the function – $http. When Angular runs the javascript, it injects a http service object into $http automatically.
3. The $http.get() does the ajax call to the auto-generated Grails Rest endpoint
4. The result data is set to a new variable in scope – “starCatalog”. We will use this variable to display the table data

Step: Display data in table

You can run crazy with your imagination on how to display the data, but a simple step is shown here:

AngularJS Directives (ng-show, ng-click, ng-controller, ng-repeat) do appear to be a cleaner way of extending html behaviour.

Directive ng-controller=StarCatalogCtrl specifies which controller provides the scope of the data

How an implicit scope variable “starCatalog” hides/shows the table (within the span tag, using the ng-show directive)

The ng-repeat Angular directive which is the “forEach (item in itemList)” equivalent to iterate through the starCatalog

With this approach, the binding between client and server is a clean http call. This gives you the ability to call any rest service, as long as you can process what you get.

And before we go nuts about AngularJS, observe the syntax of the <a> tag. This type of construct was popular pre-jquery times (<a href=”#”, onclick=”javascript:openLink()”>Click me</a>). With jQuery, there was a big drive towards separation of presentation of data and manipulation of data – using $(id).onClick() syntax. But AngularJS has put the old construct right back into vogue now, but with a twist.

Does this bother you? The pendulum of imperative-declarative programming will swing on forever. Meanwhile, take a look at these articles about Remix and Innovation Recycle bin.

In the previous post, we got karma running on your local systems, as part of grails unit test plans, enabling continual test against Chrome. How do you ensure your unit tests are running in a build server like Jenkins or Bamboo?

PhantomJS is a headless webkit, ie a browser with no browser UI. Make these changes in your karma.conf.js

Notice that Karma runs tests against PhantomJS too. You can also add Firefox, IE and test your javascripts against multiple browsers simultaneously.

Additional Notes

But for your build server you need to test just against PhantomJS and not other browsers. One way to do this, is to create a copy of karma.conf.js as karma.local-conf.js. Use the local copy for your local unit tests and the default karma.conf.js for the builds (ie only PhantomJS). This way grails test-app runs against the karma.conf.js in your build server.

Remember you need to install node.js, karma and other components in the build server too.

In Part 5, we shall see how to invoke grails urls/services from AngularJS.

There is some issue with how the karma is being started via test-app. I found both cmd line grails test-app and invoking via IntelliJ grails cmd window (Alt+G) yield different results. The common problem of both errors seems to be the port number that karma starts on.

Solutions

1. Change the port number in karma.conf.js to 8001 or try another number (above 1024 and available).
2. Remove line of the port number specified in JavaScriptUnitTestKarmaSuite.java: @KarmaTestSuiteRunner.KarmaRemoteServerPort(8001)

Results

With the above settings (ie karma.conf.js:port = 8001 and no port specified in the java code), the test-app works fine in both IntelliJ and command line.

During your test runs, sometimes the port binding is not released when test is shutdown. On *nix systems, you can just use kill <process-id>. For Windows, use PowerShell and do the following:

netstat -o -n -a | findstr "<portnumber>"
stop-process -Id <pid>

In Part 3, we saw how to add karma to grails test-app lifecycle.
In Part 4, lets see how to get karma tests running on your build server.

As of this writing, angular-mocks is at v1.2.14 and does not work with angular v1.2.12. When Karma is run, it fails with following error:

Failed to instantiate module ngMock due to Unknown provider: $$rAFProvider

I had to go back to a previous version of angular-mocks v1.2.3. So install v1.2.3:

cmd> bower install angular-mocks#1.2.3

Both angular and angular-mocks will be installed in c:/projects/angrails/test/javascript/lib/bower_components. You can delete the “angular” directory, because we already included it in the grails-app/assets. You would rather not want two angular imports in your project, as you must remember to update both for version changes.

#Answer in the following manner (of course you can choose to answer differently)

Which testing framework do you want to use ?
Press tab to list possible options. Enter to move to the next question.
> jasmine
Do you want to use Require.js ?
This will add Require.js plugin.
Press tab to list possible options. Enter to move to the next question.
> no
Do you want to capture a browser automatically ?
Press tab to list possible options. Enter empty string to move to the next question.
> Chrome
>
What is the location of your source and test files ?
You can use glob patterns, eg. "js/*.js" or "test/**/*Spec.js".
Enter empty string to move to the next question.
> ../../../grails-app/assets/bower_components/jquery/dist/jquery.js
> ../../../grails-app/assets/bower_components/angular/angular.js
> ../../../grails-app/assets/javascripts/**/*.js
> ../../../test/javascript/lib/bower_components/angular-mocks/angular-mocks.js
> ../../../test/javascript/unit/**/*.js
>
Should any of the files included by the previous patterns be excluded ?
You can use glob patterns, eg. "**/*.swp".
Enter empty string to move to the next question.
>
Do you want Karma to watch all the files and run the tests on change ?
Press tab to list possible options.
> yes
Config file generated at "c:\projects\angrails\test\javascript\config\karma.conf.js".

Optionally, you can edit the karma.conf.js and set the basepath to: basePath: ‘./../../../’, and remove the ../../../ from the file includes.

Step: Start Karma

cmd> karma start karma.conf.js

You should see a chrome browser started pointing to 9876 port. There is nothing to test yet. Keep the Karma running.

There are several posts about setting up AngularJS, but a few specific to Grails environment. If you have been a Grails developer and want to explore using AngularJS framework for front-end, here is step by step guide to get started. Grails and AngularJS are both full-fledged mvc frameworks on their own. Using the positives from both can be a killer comination to build fast and modern dynamic web applications.

Notes:

Instructions are for Windows OS

Directories only for reference

All versions as of writing this article. Substitute with newer versions as appropriate.

Pre-installed: JDK 1.7.0_51: C:\Programs\Java\jdk_1.7.0_51

Pre-installed: Grails 2.3.6: C:\Programs\Grails\grails-2.3.6

This setup does not use the angularjs-resources Grails plugin. It replaces the resources plugin entirely with asset-pipeline plugin and uses npm/bower to manage javascript dependencies directly. AngularJS does work with grails resources plugin too, but I feel it becomes difficult to maintain when adding more angular modules.

AngularJS will work with resources plugin too, but when you start installing many javascript components, the ApplicationResources can become clumsy. Asset pipeline is the new Grails plugin (based on Rails asset pipeline) that makes it easier to manage static resources, javascript, sass/less etc.